Mars is the fourth planet from the Sun and the seventh largest in the Solar System. A cold, dusty desert world with a thin atmosphere (mostly CO₂), the planet features extinct volcanoes, deep canyons, polar ice caps, and seasons. Mars has two small moons (Phobos and Deimos), a day just over 24 hours long, and a year lasting about 687 Earth days. It is a prime focus of robotic exploration and studies about past water and habitability.
Source: science.nasa.gov
26/04/2005

What goes there across the plains of Mars? A dust devil. For the first time, definitive movies of the famous spinning dust towers have been created from ground level. The robot rover Spirit has now imaged several dust devils from its hillside perch just within the past two months. Each image in the above sequence was taken about 20 seconds apart. Inspection of the digitally resized images show the passing dust devil raising Martian dust so thick that it casts a shadow. The new dust devil movies have been made possible by a new hybrid interaction system where the robot Spirit on Mars takes many images and humans on Earth inspect thumbnails and decide which full resolution images to send back.